A2: Microbes in the News (#3)


As Subway Commuters Mingle, Their Microbes Do Too

Subway riders in Hong Kong. (Credit: Sean Pavone/Shutterstock)           Hand-based microbe collecting experiment on the subway

Summary: A research group in the University of Hong Kong wanted to get a holistic view of how many microbes interact with humans in a city. They specifically studied the Hong Kong metro system which provided the team with a way to look at microbe populations throughout the city. About 5 million people are riding the metro every day. In their study, they had volunteers ride the metro during the morning and during the night. They collected bacteria by telling the volunteers to hold on to the handrails and then swab their hands (palms) after they got off the metro. The goal of their study is to understand what microbes on the metro transfer onto the riders. After the samples underwent DNA sequence analysis they discovered that the microbes the riders encountered were very dependent on time. They discovered that the morning riders were mostly exposed to microbes that belonged to the same environment surrounding different metro lines. The evening riders had a mixture of microbes some also belonging to different metro lines but the majority belonged to microbes that live on human skin. Through their study, they discovered that different metro lines had distinct populations of microbes in the morning but in the evening the populations had blended together.

Connections: During lecture, we have talked a lot about how we have an immune system to protect us from microbes. Specifically, we have an innate (non-specific) immune system which consist of physical barriers such as skin and hair. A lot of the microbes found on the hands of the volunteers belonged to a mix of different microbes found in different metro lines and microbes that are found on the human skin. Without these physical barriers a lot of people will be exposed to the microbes and could potentially get sick. We have also talked about ways of disinfecting places to prevent the spread of microbes. Even though, the metro employees were cleaning the train rails that people touched throughout the day, the commuter traffic through out the day were spreading microbes along with it. So, although the rails were being cleaned through the day the microbial spreading was still occurring.

Critical analysis: We already know that microbes are everywhere. The goal of this study wasn’t to scare the metro riders. They want to educate the public that might not fully understand what microbes are, that they are everywhere and they can spread quickly. Especially in public places, through the study they wanted to help commuters understand what they can do to protect themselves and reduce the spread of bacteria.  Many people grab these rails and then might rub their eyes or eat something without washing their hands. I think this study is important so people have better hygiene after being in public spaces. Meaning perhaps washing their hands as soon as they can or having hand sanitizer handy when they can’t wash their hands.

Question: I wonder if the rails were being cleaned though out the day for the purpose of the experiment only. Are they cleaned on a regular basis though-out the day when it’s not for   study? If not, would they have potentially found other more harmful bacteria?



2 Comments for “A2: Microbes in the News (#3)”



I think it’s really cool that this study’s aim was more to make the public aware of the microbes that surround them. I think that sort of awareness can be especially important during flu season or other outbreaks! As far as your question, I was also curious the same thing, so I looked it up! In a quick search, I came across a blog https://cheeseweb.eu/2013/08/surprised-hong-kong/
It says the metro is so clean you could eat off the floor! Also, Hong Kong in general, has a lot of signs that mention how often a facility is cleaned. So you would imagine that would all involve the handrails?



This was a very interesting article. Personally, I thought you were going to talk in your critical analysis about the fact that different microbes live in different habitats, dependent on their temperature and humidity and other environmental factors. I was thinking that the microbes were changing as a result of the environment shifting because of variable temperatures and humidity throughout the day. In relation to your question, I believe that the rails need to be cleaned every day by janitors. I would think if no one would be cleaning the rails that yes, dangerous bacteria could be living on them.

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